Apurinic/apyrimidinic endonuclease sensitive sites as intermediates in the in vitro degradation of deoxyribonucleic acid by neocarzinostatin

Neocarzinostatin (NCS) induces alkali-labile sites in DNA which are stabilized by NaBH4 reduction. The stabilized sites are sensitive to an AP endonuclease from human lymphoma cells. NCS-induced degradation of supercoiled Col E1 DNA proceeds in stepwise fashion with apurinic/apyrimidinic (AP) sites as intermediates. Degradation is increased when reaction occurs in the presence of AP endonuclease, and DNA reacted with NCS can be shown to have numerous AP endonuclease sensitive sites.